This invention relates to lighting and exposure equipment for still photographic processes, and specifically to an apparatus which allows for the precise and consistent sequencing of multiple light sources and photographic filters, and for precise and consistent exposure modification through the electronic modulation of the sequencing.
It is common for photographers who are practiced in the field of product or still photography to utilize multiple light sources and filters in the setup and execution of a complex photographic exposure of an object or scene. For necessity of proper exposure and desired effect, light sources of mixed type, intensity, and duration are employed, simultaneously or sequentially. Such sequences are most commonly executed in a non-automated manner, involving trial-and-error of timing, exposure calculations, light switching, multiple power sourcing, and filter changing.
An additional process involved in these types of exposures is known as `bracketing`, in which the photographer will underexpose and overexpose the photographic scene in multiple attempts to procure a range of selectable results. Bracketing is commonly achieved through the modulation of two factors, either the diameter of the camera aperture, known as the `f-stop`, or the time duration that the film is exposed to the light passing through the aperture, known as the `shutter speed`. The difficulties in such a bracketing technique are the loss of a consistent depth-of-field, or focus, when the f-stop is modulated, and the loss of a consistent length of exposure when the shutter speed is modulated.
The continuous switching on and off of lamps, the exchanging of filters, and the manual lighting of objects with moveable lamps all require a great deal of coordination and effort. This is an inexact method for the exposure of a subject and does not lend itself to efficient, precise, and repeatable results. Difficulties include non-centralized power sources for all the lights needed for the exposure; the inexact repetition of lighting durations due to the longhand manner of their calculations; separate stands for cameras and camera filters; the inexact placement of filters due to the common hand-held technique; and the inexact repetition of lighting patterns due to hand-held lamps or light wands. Additionally, the current technique of bracketing through the use of f-stop or shutter speed is a potential limitation when both f-stop and shutter speed must be fixed for complex aesthetic results.
An apparatus is needed to provide a programmable controlling device which sequences multiple light sources in an efficient, precise, and repeatable manner.
An apparatus is also needed to provide a centralized power actuator unit which is synchronized with the controlling device, so that multiple and varied light sources may be precisely engaged and disengaged at one point of voltage supply.
An apparatus is also needed to provide close-range light sources of low voltage and intensity, so that the object being photographed may be lighted precisely over an extended period of time during the programmed lighting sequences, without the light sources themselves appearing on the exposure.
An apparatus is also needed to provide mounting mechanisms for the close-range lights, so that the lights may be moved in and out of the photographic scene both during and between the exposure in a precise and repeatable manner.
Additionally, there is a need for an apparatus to incorporate into this sequencing system a precision filter changing device, allowing for a plurality of filters to be individually or collectively engaged at specific moments during the lighting actuation.
Finally, an apparatus is needed to digitally modulate the lighting and filtering sequences of the photographic system, so that the technique of bracketing may be achieved through the discrete modulation of the lighting duration as opposed to the unfavorable alteration of either f-stop or shutter speed--a process which to date has been unachievable in a predictable manner.